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Tsuchiya, M, Talley LD.  1998.  A Pacific hydrographic section at 88 degrees W: Water-property distribution. Journal of Geophysical Research-Oceans. 103:12899-12918.   10.1029/97jc03415   AbstractWebsite

Full-depth conductivity-temperature-depth (CTD)/hydrographic measurements with high horizontal and vertical resolution were made in February-April 1993 along a line lying at a nominal longitude of 88 degrees W and extending from southern Chile (54 degrees S) to Guatemala (14 degrees N). It crossed five major deep basins (Southeast Pacific, Chile, Peru, Panama, and Guatemala basins) east of the East Pacific Rise. Vertical sections of potential temperature, salinity, potential density, oxygen, silica, phosphate, nitrate, and nitrite are presented to illustrate the structure of the entire water column. Some features of interest found in the sections are described, and an attempt is made to interpret them in terms of the isopycnal property distributions associated with the large-scale ocean circulation. These features include: various near-surface waters observed in the tropical and subtropical regions and the fronts that mark the boundaries of these waters; the possible importance of salt fingering to the downward salt transfer from the high-salinity subtropical water; a shallow thermostad (pycnostad) developed at 16 degrees-18.5 degrees C in the subtropical water; low-salinity surface water in the subantarctic zone west of southern Chile; large domains of extremely low oxygen in the subpycnocline layer on both sides of the equator and a secondary nitrite maximum associated with a nitrate minimum in these low-oxygen domains; high-salinity, low-oxygen, high-nutrient subpycnocline water that is carried poleward along the eastern boundary by the Peru-Chile Undercurrent; the Subantarctic Mode and Antarctic Intermediate waters; middepth isopycnal property extrema observed at the crest of the Sala y Gomez Ridge; influences of the North Pacific and the North Atlantic upon deep waters along the section; and the characteristics and sources of the bottom waters in the five deep basins along the section.

Tsuchiya, M, Talley LD, McCartney MS.  1994.  Water-Mass Distributions in the Western South-Atlantic - a Section from South Georgia Island (54s) Northward across the Equator. Journal of Marine Research. 52:55-&.   10.1357/0022240943076759   AbstractWebsite

A long CTD/hydrographic section with closely spaced stations was made in February-April 1989 in the western Atlantic Ocean between 0-degrees-40'N and South Georgia (54S) along a nominal longitude of 25W. Vertical sections of various properties from CTD and discrete water-sample measurements are presented and discussed in terms of the large-scale circulation of the South Atlantic Ocean. One of the most important results is the identification of various deep-reaching fronts in relation to the large-scale circulation and the distribution of mode waters. Five major fronts are clearly defined in the thermal and salinity fields. These are the Polar (49.5S), Subantarctic (45S), Subtropical (41-42S), Brazil Current (35S) Fronts, and an additional front at 20-22S. The first three are associated with strong baroclinic shear. The Brazil Current Front is a boundary between the denser and lighter types of the Subantarctic Mode Water (SAMW), and the 20-22S front marks the boundary between the anticyclonic subtropical and cyclonic subequatorial gyres. The latter front coincides with the northern terminus of the high-oxygen tongue of the Antarctic Intermediate Water (AAIW) and also with the abrupt shift in density of the high-silica tongue originating in the Upper Circumpolar Water and extending northward. Two pycnostads with temperatures 20-24-degrees-C are observed between 10S and 25S with the denser one in the subtropical and the other lighter one in the subequatorial gyre. A weak thermostad centered at 4-degrees-C occurs in the AAIW between the Subtropical Front and the Subantarctic Front and shows characteristics similar to the densest variety of the SAMW. Another significant result is a detailed description of the complex structure of the deep and bottom waters. The North Atlantic Deep Water (NADW) north of 25S contains two vertical maxima of oxygen (at 2000 m and 3700 m near the equator) separated by intervening low-oxygen water with more influence from the Circumpolar Water. Each maximum is associated with a maximum of salinity and minima of nutrients. The deeper salinity maximum is only weakly defined and is limited to north of 18S, appearing more as vertically uniform salinity. South of 25S the NADW shows only a single maximum of salinity, a single maximum of oxygen, and a single minimum of each nutrient, all lying close together. The salinity maximum south of 25S and the deeper oxygen/salinity maximum north of 1 IS are derived from the same source waters. The less dense NADW containing the shallower extrema of characteristics turns to the east at lower latitudes and does not reach the region south of 25S. The southward spreading of the NADW is interrupted by domains of intensified circumpolar characteristics. This structure is closely related to the basin-scale gyre circulation pattern. The Weddell Sea Deep Water is the densest water we observed and forms a relatively homogeneous layer at the bottom of the Georgia and Argentine Basins. The bottom layer of the Brazil Basin is occupied by the vertically and laterally homogeneous Lower Circumpolar Water.

Tsuchiya, M, Talley LD.  1996.  Water-property distributions along an eastern Pacific hydrographic section at 135W. Journal of Marine Research. 54:541-564.   10.1357/0022240963213583   AbstractWebsite

As part of the World Ocean Circulation Experiment, full-depth CTD/hydrographic measurements with high horizontal and vertical resolutions were made in June-August 1991 along a line extending from 34N to 33S at a nominal longitude of 135W with an additional short leg that connects it to the California coast roughly along 34N. The line spans the major part of the subtropical and intertropical circulation regime of the eastern North and South Pacific. The primary purpose of this paper is to present vertical sections of various properties from CTD and discrete water-sample measurements along this line and to give an overview of some important features as a basis for more comprehensive basin-scale studies. These features include: the frontal structures found in the surface-layer salinity field in the North Pacific; relatively high-salinity water that dominates the subpycnocline layer between the equator and 17N; troughs of the subpycnocline isopycnals for 26.8-27.5 sigma(theta) found at 12N and 12.5S; a permanent thermostad at 9-10 degrees C observed between 4.5N and 15N; the pycnostad of the Subantarctic Mode Water centered at 27.0-27.05 sigma(theta) and developed south of 22S; two types of the Antarctic Intermediate Water representing the subtropical and equatorial circulation regimes; a thick tongue of high silica centered at 3000 m (45.8 sigma(4)) and extending southward across the entire section; deep (2000-3000 m) westward flows at 5-8N and 10-15S separated by an eastward flow at 1-2S; and dense, cold, oxygen-rich, nutrient-poor bottom waters, which are associated with fracture zones and believed to represent the pathways of eastward flows into the Northeast Pacific Basin of the bottom waters separated from the northward-flowing western boundary undercurrent. This work once again demonstrates the usefulness of long lines of high-quality, high-resolution hydrographic stations such as the one described herein in advancing the understanding of the large-scale ocean circulation.

Tsuchiya, M, Talley LD, McCartney MS.  1992.  An Eastern Atlantic Section from Iceland Southward across the Equator. Deep-Sea Research Part a-Oceanographic Research Papers. 39:1885-1917.   10.1016/0198-0149(92)90004-d   AbstractWebsite

A long CTD/hydrographic section with closely-spaced stations was occupied in July-August 1988 from Iceland southward to 3-degrees-S along a nominal longitude of 20-degrees-W. The section extends from the surface down to the bottom, and spans the entire mid-ocean circulation regime of the North Atlantic from the subpolar gyre through the subtropical gyre and the equatorial currents. Vertical sections of potential temperature, salinity and potential density from CTD measurements and of oxygen, silica, phosphate and nitrate, based on discrete water-sample measurements are presented and discussed in the context of the large-scale circulation of the North Atlantic Ocean. The close spacing of high-quality stations reveals some features not described previously. The more important findings include: (1) possible recirculation of the lightest Subpolar Mode Water into the tropics; (2) a thermostad at temperatures of 8-9-degrees-C, lying below that of the Equatorial 13-degrees-C Water; (3) the nutrient distribution in the low-salinity water above the Mediterranean Outflow Water that supports the previous conjecture of northern influence of the Antarctic Intermediate Water; (4) a great deal of lateral structure of the Mediterranean Outflow Water, with a number of lobes of high salinity; (5) an abrupt southern boundary of the Labrador Sea Water at the Azores-Biscay Rise and a vertically well-mixed region to its south; (6) a sharp demarcation in the central Iceland Basin between the newest Iceland-Scotland Overflow Water and older bottom water, which has a significant component of southern water; (7) evidence that the Northeast Atlantic Deep Water is a mixture of the Mediterranean Outflow Water and the Northwest Atlantic Bottom Water with very little input from the Iceland-Scotland Overflow Water; (8) an isolated core of the high-salinity, low-silica Upper North Atlantic Deep Water at the equator; (9) a core of the high-oxygen, low-nutrient Lower North Atlantic Deep Water pressed against the southern flank of the Mid-Atlantic Ridge just south of the equator; (10) a weak minimum of salinity, and well-defined maxima of nutrients associated with the oxygen minimum that separates the Middle and Lower North Atlantic Deep Waters south of the equator; (11) a large body of nearly homogeneous water beneath the Middle North Atlantic Deep Water between 20-degrees-N and the Azores-Biscay Rise; and (12) a deep westward boundary undercurrent on the southern slope of the Rockall Plateau.

Treguier, AM, Theetten S, Chassignet EP, Penduff T, Smith R, Talley L, Beismann JO, Boning C.  2005.  The North Atlantic subpolar gyre in four high-resolution models. Journal of Physical Oceanography. 35:757-774.   10.1175/jpo2720.1   AbstractWebsite

The authors present the first quantitative comparison between new velocity datasets and high-resolution models in the North Atlantic subpolar gyre [1/10 degrees Parallel Ocean Program model (POPNA10), Miami Isopycnic Coordinate Ocean Model (MICOM), 1/6 degrees Atlantic model (ATL6), and Family of Linked Atlantic Ocean Model Experiments (FLAME)]. At the surface, the model velocities agree generally well with World Ocean Circulation Experiment (WOCE) drifter data. Two noticeable exceptions are the weakness of the East Greenland coastal current in models and the presence in the surface layers of a strong southwestward East Reykjanes Ridge Current. At depths, the most prominent feature of the circulation is the boundary current following the continental slope. In this narrow flow, it is found that gridded float datasets cannot be used for a quantitative comparison with models. The models have very different patterns of deep convection, and it is suggested that this could be related to the differences in their barotropic transport at Cape Farewell. Models show a large drift in watermass properties with a salinization of the Labrador Sea Water. The authors believe that the main cause is related to horizontal transports of salt because models with different forcing and vertical mixing share the same salinization problem. A remarkable feature of the model solutions is the large westward transport over Reykjanes Ridge [10 Sv (Sv = 10(6) m(3) s(-1)) or more].

Tishchenko, PY, Talley LD, Lobanov VB, Nedashkovskii AP, Pavlova GY, Sagalaev SG.  2007.  The influence of geochemical processes in the near-bottom layer on the hydrochemical characteristics of the waters of the Sea of Japan. Oceanology. 47:350-359.   10.1134/s0001437007030071   AbstractWebsite

According to the results of the international expedition aboard the R/Vs Roger Revelle and Professor Khromov in the summer 1999, areas with low oxygen contents (below 210 mu M/kg) and those with increased contents of dissolved inorganic carbon and phosphates were found that roughly coincided with one another. These areas are located near the bottom on the southwestern slope of the Tsushima Basin in the region of the Korea Strait and on the continental slope in the region of the Tatar Strait in the northern part of the sea at about 46 degrees N. The set of hydrochemical data points to a high geochemical activity in the near-bottom layer of the areas noted. This activity is confirmed by direct observations of the composition of the interstitial water in the sediments collected in the northern part of the sea during the expedition of R/V Akademik M.A. Lavrent'ev in 2003. It was supposed that the main cause of the increased geochemical activity is the runoff of suspended and dissolved matter from the Korea and Tatar straits. In the areas mentioned, the near-bottom waters are characterized by low values of the nitrogen-phosphorus ratio (below 10), which is geochemical proof of the denitrification process occurring under the conditions of high oxygen concentrations characteristic of the Sea of Japan. Based on the value of the annual production in the Sea of Japan, a rate of denitrification equal to 3.4 x 10(12) gN/year was calculated. Hence, it is confirmed that the geochemical processes in the near-bottom layer have a direct influence on the spatiotemporal characteristics of the hydrochemical properties of the waters of the Sea of Japan.

Tishchenko, PY, Talley LD, Nedashkovskii AP, Sagalaev SG, Zvalinskii VI.  2002.  Temporal variability of the hydrochemical properties of the waters of the Sea of Japan. Oceanology. 42:795-803. AbstractWebsite

Hydrochemical studies were performed in the Sea of Japan from onboard R/V Akademik Vinogradov in 1992 and R/Vs Roger Revelle and Professor Khromov in 1999. A comparison of the hydrochemical properties (concentrations of dissolved oxygen and nutrients and proteins of the carbonate system) of the waters of the Sea of Japan with those of the adjacent basins (the Sea of Okhotsk, Pacific Ocean, and East China Sea) demonstrates significant differences between them. In addition, a significant temporal variability of the hydrochemical properties of the intermediate and abyssal waters of the Sea of Japan was revealed. A general increase in the contents of inorganic forms of phosphorus, nitrogen, and normalized organic matter along with a general decrease in the oxygen concentration and normalized alkalinity with time was established. We suggest a model for an open basin, in which the principal reason for the observed features and temporal variability of the hydrochemical properties is related to the water exchange between the Sea of Japan and adjacent basins. A supposition is posed on the strong dependence of the water exchange on the variability of the intensity analysis direction of the major currents of the northwestern Pacific Ocean, especially the Kuroshio Current.

Tishchenko, PY, Talley LD, Lobanov VB, Zhabin IA, Luchm VA, Nedashkovskii AP, Sagalaev SG, Chichkin RV, Shkirnikova EM, Ponomarev VI, Masten D, Kang DJ, Kim KR.  2003.  Seasonal variability of the hydrochemical conditions in the sea of Japan. Oceanology. 43:643-655. AbstractWebsite

In the summer of 1999 and the winter of 2000, during international expeditions of R/Vs Professor Khromov and Roger Revelle, hydrological and hydrochemical studies of the Sea of Japan were performed. Comparing the hydrochemical characteristics of the Sea of Japan in the summer and winter seasons, we have found that the seasonal variability affects not only the upper quasihomogeneous layer but also the deeper layers. This variability is caused by the intensification of vertical mixing during the winter season. It was shown that the mixing intensification in the deep layers of the sea in the winter might be caused both by the slope convection and by the deep convection in the open part of the sea, penetrating deeper than 1000 in. It was found that the area of positive values of the biological constituent of the apparent oxygen consumption coincides with the area of deep convection. The climatic zoning in the distribution of partial pressure of carbon dioxide was revealed for both seasons. In the northwestern part of the sea, carbon dioxide is released into the atmosphere due to the deep convection in the winter and the heating process in the summer. The southern part of the sea absorbs the atmospheric carbon dioxide because of the process of photosynthesis and cooling of the waters supplied from the Korea Strait.

Tamsitt, V, Drake HF, Morrison AK, Talley LD, Dufour CO, Gray AR, Griffies SM, Mazloff MR, Sarmiento JL, Wang J, Weijer W.  2017.  Spiraling pathways of global deep waters to the surface of the Southern Ocean. Nature Communications. 8:172.   10.1038/s41467-017-00197-0   Abstract

Upwelling of global deep waters to the sea surface in the Southern Ocean closes the global overturning circulation and is fundamentally important for oceanic uptake of carbon and heat, nutrient resupply for sustaining oceanic biological production, and the melt rate of ice shelves. However, the exact pathways and role of topography in Southern Ocean upwelling remain largely unknown. Here we show detailed upwelling pathways in three dimensions, using hydrographic observations and particle tracking in high-resolution models. The analysis reveals that the northern-sourced deep waters enter the Antarctic Circumpolar Current via southward flow along the boundaries of the three ocean basins, before spiraling southeastward and upward through the Antarctic Circumpolar Current. Upwelling is greatly enhanced at five major topographic features, associated with vigorous mesoscale eddy activity. Deep water reaches the upper ocean predominantly south of the Antarctic Circumpolar Current, with a spatially nonuniform distribution. The timescale for half of the deep water to upwell from 30° S to the mixed layer is ~60–90 years.

Tamsitt, V, Talley LD, Mazloff MR.  2019.  A deep eastern boundary current carrying Indian deep water south of Australia. Journal of Geophysical Research: Oceans. 124:2218-2238.   10.1029/2018jc014569   Abstract

In the Southern Hemisphere, the ocean's deep waters are predominantly transported from low to high latitudes via boundary currents. In addition to the Deep Western Boundary Currents, pathways along the eastern boundaries of the southern Atlantic, Indian, and Pacific transport deep water poleward into the Southern Ocean where these waters upwell to the sea surface. These deep eastern boundary currents and their physical drivers are not well characterized, particularly those carrying carbon and nutrient-rich deep waters from the Indian and Pacific basins. Here we describe the poleward deep eastern boundary current that carries Indian Deep Water along the southern boundary of Australia to the Southern Ocean using a combination of hydrographic observations and Lagrangian experiments in an eddy-permitting ocean state estimate. We find strong evidence for a deep boundary current carrying the low-oxygen, carbon-rich signature of Indian Deep Water extending between 1,500 and 3,000 m along the Australian continental slope, from 30°S to the Antarctic Circumpolar Current southwest of Tasmania. From the Lagrangian particles it is estimated that this pathway transports approximately 5.8 ± 1.3 Sv southward from 30°S to the northern boundary of the Antarctic Circumpolar Current. The volume transport of this pathway is highly variable and is closely correlated with the overlying westward volume transport of the Flinders Current.

Tamsitt, V, Abernathey RP, Mazloff MR, Wang J, Talley LD.  2018.  Transformation of deep water masses along Lagrangian upwelling pathways in the Southern Ocean. Journal of Geophysical Research: Oceans.   10.1002/2017JC013409   AbstractWebsite

Upwelling of northern deep waters in the Southern Ocean is fundamentally important for the closure of the global meridional overturning circulation and delivers carbon and nutrient‐rich deep waters to the sea surface. We quantify water mass transformation along upwelling pathways originating in the Atlantic, Indian, and Pacific and ending at the surface of the Southern Ocean using Lagrangian trajectories in an eddy‐permitting ocean state estimate. Recent related work shows that upwelling in the interior below about 400 m depth is localized at hot spots associated with major topographic features in the path of the Antarctic Circumpolar Current, while upwelling through the surface layer is more broadly distributed. In the ocean interior upwelling is largely isopycnal; Atlantic and to a lesser extent Indian Deep Waters cool and freshen while Pacific deep waters are more stable, leading to a homogenization of water mass properties. As upwelling water approaches the mixed layer, there is net strong transformation toward lighter densities due to mixing of freshwater, but there is a divergence in the density distribution as Upper Circumpolar Deep Water tends become lighter and dense Lower Circumpolar Deep Water tends to become denser. The spatial distribution of transformation shows more rapid transformation at eddy hot spots associated with major topography where density gradients are enhanced; however, the majority of cumulative density change along trajectories is achieved by background mixing. We compare the Lagrangian analysis to diagnosed Eulerian water mass transformation to attribute the mechanisms leading to the observed transformation.

Tamsitt, V, Talley LD, Mazloff MR, Cerovecki I.  2016.  Zonal variations in the Southern Ocean heat budget. Journal of Climate. 29:6563-6579.   10.1175/JCLI-D-15-0630.1   AbstractWebsite

The spatial structure of the upper ocean heat budget in the Antarctic Circumpolar Current (ACC) is investigated using the ⅙°, data-assimilating Southern Ocean State Estimate (SOSE) for 2005–10. The ACC circumpolar integrated budget shows that 0.27 PW of ocean heat gain from the atmosphere and 0.38 PW heat gain from divergence of geostrophic heat transport are balanced by −0.58 PW cooling by divergence of Ekman heat transport and −0.09 PW divergence of vertical heat transport. However, this circumpolar integrated balance obscures important zonal variations in the heat budget. The air–sea heat flux shows a zonally asymmetric pattern of ocean heat gain in the Indian and Atlantic sectors and ocean heat loss in the Pacific sector of the ACC. In the Atlantic and Indian sectors of the ACC, the surface ocean heat gain is primarily balanced by divergence of equatorward Ekman heat transport that cools the upper ocean. In the Pacific sector, surface ocean heat loss and cooling due to divergence of Ekman heat transport are balanced by warming due to divergence of geostrophic heat advection, which is similar to the dominant heat balance in the subtropical Agulhas Return Current. The divergence of horizontal and vertical eddy advection of heat is important for warming the upper ocean close to major topographic features, while the divergence of mean vertical heat advection is a weak cooling term. The results herein show that topographic steering and zonal asymmetry in air–sea exchange lead to substantial zonal asymmetries in the heat budget, which is important for understanding the upper cell of the overturning circulation.

Talley, LD, Rosso I, Kamenkovich I, Mazloff MR, Wang J, Boss E, Gray AR, Johnson KS, Key RM, Riser SC, Williams NL, Sarmiento JL.  2019.  Southern Ocean biogeochemical float deployment strategy, with example from the Greenwich meridian line (GO-SHIP A12). Journal of Geophysical Research-Oceans. 124:403-431.   10.1029/2018jc014059   AbstractWebsite

Biogeochemical Argo floats, profiling to 2,000-m depth, are being deployed throughout the Southern Ocean by the Southern Ocean Carbon and Climate Observations and Modeling program (SOCCOM). The goal is 200 floats by 2020, to provide the first full set of annual cycles of carbon, oxygen, nitrate, and optical properties across multiple oceanographic regimes. Building from no prior coverage to a sparse array, deployments are based on prior knowledge of water mass properties, mean frontal locations, mean circulation and eddy variability, winds, air-sea heat/freshwater/carbon exchange, prior Argo trajectories, and float simulations in the Southern Ocean State Estimate and Hybrid Coordinate Ocean Model (HYCOM). Twelve floats deployed from the 2014-2015 Polarstern cruise from South Africa to Antarctica are used as a test case to evaluate the deployment strategy adopted for SOCCOM's 20 deployment cruises and 126 floats to date. After several years, these floats continue to represent the deployment zones targeted in advance: (1) Weddell Gyre sea ice zone, observing the Antarctic Slope Front, and a decadally-rare polynya over Maud Rise; (2) Antarctic Circumpolar Current (ACC) including the topographically steered Southern Zone chimney where upwelling carbon/nutrient-rich deep waters produce surprisingly large carbon dioxide outgassing; (3) Subantarctic and Subtropical zones between the ACC and Africa; and (4) Cape Basin. Argo floats and eddy-resolving HYCOM simulations were the best predictors of individual SOCCOM float pathways, with uncertainty after 2years of order 1,000km in the sea ice zone and more than double that in and north of the ACC.

Talley, L, Fine R, Lumpkin R, Maximenko N, Morrow R.  2010.  Surface Ventilation and Circulation. Proceedings of OceanObs’09: Sustained Ocean Observations and Information for Society. 1( Hall J, Harrison DE, Stammer D, Eds.).   10.5270/OceanObs09.pp.38   Abstract
Talley, LD, de Szoeke RA.  1986.  Spatial Fluctuations North of the Hawaiian Ridge. Journal of Physical Oceanography. 16:981-984.   10.1175/1520-0485(1986)016<0981:sfnoth>;2   AbstractWebsite

A closely spaced hydrographic section from Oabu, Hawaii to 28°N, 152°W and then north along 152°W shows strong eddy or current features with dynamic height signatures of about 30 dyn cm across 150 km and associated geostrophic surface velocities of approximately 60 cm s−1. Two such features are found between Hawaii and the Subtropical Front, which is located at 32°N. Similar features have been observed on a number of other hydrographic and XBT sections perpendicular to the Hawaiian Ridge. It is hypothesized that the features are semipermanent, are due to the presence of the Ridge, and are related to the North Hawaiian Ridge Current of Mysak and Magaard.

Talley, LD, Lobanov V, Ponomarev V, Salyuk A, Tishchenko P, Zhabin I, Riser S.  2003.  Deep convection and brine rejection in the Japan Sea. Geophysical Research Letters. 30   10.1029/2002gl016451   AbstractWebsite

Direct water mass renewal through convection deeper than 1000 m and the independent process of dense water production through brine rejection during sea ice formation occur at only a limited number of sites globally. Our late winter observations in 2000 and 2001 show that the Japan (East) Sea is a part of both exclusive groups. Japan Sea deep convection apparently occurs every winter, but massive renewal of bottom waters through brine rejection had not occurred for many decades prior to the extremely cold winter of 2001. The sites for both renewal mechanisms are south of Vladivostok, in the path of cold continental air outbreaks.

Talley, LD.  1997.  North Pacific intermediate water transports in the mixed water region. Journal of Physical Oceanography. 27:1795-1803.   10.1175/1520-0485(1997)027<1795:npiwti>;2   AbstractWebsite

Initial mixing between the subtropical and subpolar waters of Kuroshio and Oyashio origin occurs in the mixed water region (interfrontal zone) between the Kuroshio and Oyashio. The relatively fresh water that enters the Kuroshio Extension from the Mixed Water Region is this already mixed subtropical transition water. Subtropical transition water in the density range 26.64-27.4 sigma(theta) can be considered to be the newest North Pacific Intermediate Water (NPIW) in the subtropical gyre; this density range is approximately that which is ventilated in the subpolar gyre with significant influence from the Okhotsk Sea. Freshening of the Kuroshio Extension core occurs between 140 degrees and 165 degrees E in the upper part of the NPIW (26.64-27.0 sigma(theta)), with the greatest freshening associated with the eastern side of the first and second Kuroshio meanders. Kuroshio Extension freshening in the lower part of the NPIW (27.0-27.4 sigma(theta)) occurs more gradually and farther to the east. There is nearly no distinction in water properties north and south of the Kuroshio Extension by 175 degrees W. The upper part of the NPIW in the Mixed Water Region progresses from very intrusive and including much freshwater in the west, to much smoother and more saline water in the east. The lower part of the NPIW in the mixed water region progresses from very intrusive and fresh in the far west, to noisy and more saline at 152 degrees E, to smooth and fresher in the east. These suggest a difference between the two layers in both advection direction and possibly transport across the Subarctic Front. Assuming that all waters in the region are an isopycnal mixture of subtropical and subpolar water, the zonal transport of subpolar water in the subtropical gyre at 152 degrees E is estimated at about 3 Sv (Sv = 10(6) m(3) s(-1)). This could be approximately one-quarter of the Oyashio transport in this density range.

Talley, LD.  1993.  Distribution and Formation of North Pacific Intermediate Water. Journal of Physical Oceanography. 23:517-537.   10.1175/1520-0485(1993)023<0517:dafonp>;2   AbstractWebsite

The North Pacific Intermediate Water (NPIW), defined as the main salinity minimum in the subtropical North Pacific, is examined with respect to its overall property distributions. These suggest that NPIW is formed only in the northwestern subtropical gyre; that is, in the mixed water region between the Kuroshio Extension and Oyashio front. Subsequent modification along its advective path increases its salinity and reduces its oxygen. The mixed water region is studied using all bottle data available from the National Oceanographic Data Center, with particular emphasis on several winters. Waters from the Oyashio, Kuroshio, and the Tsugaru Warm Current influence the mixed water region, with a well-defined local surface water mass formed as a mixture of the surface waters from these three sources. Significant salinity minima in the mixed water region are grouped into those that are directly related to the winter surface density and are found at the base of the oxygen-saturated surface layer, and those that form deeper, around warm core rings. Both could be a source of the more uniform NPIW to the east, the former through preferential erosion of the minima from the top and the latter through simple advection. Both sources could exist all year with a narrowly defined density range that depends on winter mixed-layer density in the Oyashio region.

Talley, LD.  2007.  Hydrographic Atlas of the World Ocean Circulation Experiment (WOCE). Volume 2: Pacific Ocean. ( Sparrow M, Chapman P, Gould J, Eds.)., Southampton, UK: International WOCE Project Office Abstract


Talley, LD.  1983.  Radiating Instabilities of Thin Baroclinic Jets. Journal of Physical Oceanography. 13:2161-2181.   10.1175/1520-0485(1983)013<2161:riotbj>;2   AbstractWebsite

The linear stability of thin, quasi-geostrophic, two-layer zonal jets on the β-plane is considered. The meridional structure of the jets is approximated in such a way as to allow an exact dispersion relation to be found. Necessary conditions for instability and energy integrals are extended to these piece-wise continuous profiles. The linearly unstable modes which arise can be related directly to instabilities arising from the vertical and horizontal shear. It is found empirically that the necessary conditions for instability are sufficient for the cases considered. Attention is focused on unstable modes that penetrate far into the locally stable ocean interior and which are found when conditions allow the jet instability phase speeds to overlap the far-field. free-wave phase speeds. These radiating instabilities exist in addition to more unstable waves which are trapped within a few deformation radii of the jet. The growth rates of the radiating instabilities depend strongly on the size of the overlap of instability and free-wave phase speeds. The extreme cases of this are westward jets which have vigorously growing, radiating instabilities and purely eastward jets which do not radiate at all. Radiating instabilities are divided into two types: a subset of the jets' main unstable waves near marginal stability and instabilities which appear to be destabilized free waves of the interior ocean. It is suggested that the fully developed field of instabilities of a zonal current consists of the most unstable, trapped waves directly in the current with a shift to less unstable, radiating waves some distance from the current. A brief comparison of the model results with observations south of the Gulf Stream is made.

Talley, LD, Yun JY.  2001.  The role of cabbeling and double diffusion in setting the density of the North Pacific intermediate water salinity minimum. Journal of Physical Oceanography. 31:1538-1549.   10.1175/1520-0485(2001)031<1538:trocad>;2   AbstractWebsite

The top of the North Pacific Intermediate Water (NPIW) in the subtropical North Pacific is identified with the main salinity minimum in the density range sigma (theta) = 26.7-26.8. The most likely source of low salinity for the NPIW salinity minimum is the Oyashio winter mixed layer, of density sigma (theta) = 26.5- 26.65. The Oyashio waters mix with Kuroshio waters in the broad region known as the Mixed Water Region (MWR), between the separated Kuroshio and Oyashio Fronts just east of Japan. It is shown that cabbeling during mixing of the cold, fresh Oyashio winter mixed layer water with the warm, saline Kuroshio water increases the density of the mixture by up to sigma (theta) = 0.07 at densities around sigma (theta) = 26.6-26.65, regardless of the mixing mechanism. Thus cabbeling accounts for about half of the observed density difference between the Oyashio winter mixed layer water and the top of the NPIW. Double diffusion during mixing of the interleaving layers of Oyashio and Kuroshio waters in the MWR can also change the density of the mixing intrusions. Density ratios favorable to double diffusion are shown to be especially prominent in Oyashio intrusions into a Kuroshio warm core ring in the 1989 data examined here. The average potential temperature-salinity profile of the new subtropical NPIW just east of the MWR, with its nearly uniform salinity, suggests the dominance of salt fingering over diffusive layering. Using the observed salinity and density differences between Oyashio surface water and the NPIW salinity minimum, after subtracting the density difference ascribed to cabbeling, an effective flux ratio of about 0.8 is estimated for possible double diffusive processes in the MWR.

Talley, LD.  1996.  Antarctic Intermediate Water in the South Atlantic. The South Atlantic : present and past circulation. ( Wefer G, Berger WH, Siedler G, Webb D, Eds.).:219-238., Berlin ; New York: Springer Abstract
Talley, LD, Feely RA, Sloyan BM, Wanninkhof R, Baringer MO, Bullister JL, Carlson CA, Doney SC, Fine RA, Firing E, Gruber N, Hansell DA, Ishii M, Johnson GC, Katsumata K, Key RM, Kramp M, Langdon C, Macdonald AM, Mathis JT, McDonagh EL, Mecking S, Millero FJ, Mordy CW, Nakano T, Sabine CL, Smethie WM, Swift JH, Tanhua T, Thurnherr AM, Warner MJ, Zhang J-Z.  2016.  Changes in Ocean Heat, Carbon Content, and Ventilation: A Review of the First Decade of GO-SHIP Global Repeat Hydrography. Annual Review of Marine Science. 8:185-215.   10.1146/annurev-marine-052915-100829   AbstractWebsite

Global ship-based programs, with highly accurate, full water column physical and biogeochemical observations repeated decadally since the 1970s, provide a crucial resource for documenting ocean change. The ocean, a central component of Earth's climate system, is taking up most of Earth's excess anthropogenic heat, with about 19% of this excess in the abyssal ocean beneath 2,000 m, dominated by Southern Ocean warming. The ocean also has taken up about 27% of anthropogenic carbon, resulting in acidification of the upper ocean. Increased stratification has resulted in a decline in oxygen and increase in nutrients in the Northern Hemisphere thermocline and an expansion of tropical oxygen minimum zones. Southern Hemisphere thermocline oxygen increased in the 2000s owing to stronger wind forcingand ventilation. The most recent decade of global hydrography has mapped dissolved organic carbon, a large, bioactive reservoir, for the first time and quantified its contribution to export production (∼20%) and deep-ocean oxygen utilization. Ship-based measurements also show that vertical diffusivity increases from a minimum in the thermocline to a maximum within the bottom 1,500 m, shifting our physical paradigm of the ocean's overturning circulation.

Talley, LD, Joyce TM, de Szoeke RA.  1991.  Transpacific Sections at 47-Degrees-N and 152-Degrees-W - Distribution of Properties. Deep-Sea Research Part a-Oceanographic Research Papers. 38:S63-S82.   10.1016/S0198-0149(12)80005-7   AbstractWebsite

Three CTD/hydrographic sections with closely-spaced stations were occupied between May 1984 and May 1987, primarily in the subpolar North Pacific. Vertical sections of CTD quantities, oxygen and nutrients are presented. Upper water properties suggest that the Subarctic Front is located south of the subtropical/subpolar gyre boundary at 152-degrees-W, that there is leakage of North Pacific Intermediate Water from the subtropical to the subpolar gyre in the eastern Pacific, and verify the poleward shift of the subtropical gyre center with depth. At intermediate depths (1000-2000 m), a separation between the western and eastern parts of the subpolar gyre is found at 180-degrees along 47-degrees-N. Abyssal waters are oldest in the northeast, with primary sources indicated at the western boundary and north of the Hawaiian Ridge. Properties and geostrophic velocity from detailed crossings of the boundary trenches suggest that flow in the bottom of the Kuril-Kamchatka Trench at the western boundary at 42-degrees-N and 47-degrees-N is northward. Very narrow boundary layers at intermediate depths are revealed in silica, as well as in the dynamical properties, at both the western and northern boundaries, and probably reflect southward and westward flow.